. GARAGE FLOOR COATINGS: IDENTIFYING WATERBORNE EPOXIES

WITH OPTIMUM HANDLING AND PERFORMANCE PROPERTIES

David Dubowik

Air Products & Chemicals Incorporated 7201 Hamilton Boulevard

Allentown, Pa. 18195 Telephone: 610-481-6277

e mail: dubowid@apci.com

Presented at the TRFA Annual Meeting Montreal, Quebec, Canada

September 10 - 12, 2006 This paper is presented by invitation of TRFA. It is publicly distributed upon request by the TRFA to assist in the communication of information and viewpoints relevant to the thermoset industry. The paper and its contents have not been reviewed or evaluated by the TRFA and should not be construed as having been adopted or endorsed by the TRFA.

GARAGE FLOOR COATINGS: IDENTIFYING WATERBORNE EPOXIES

WITH OPTIMUM HANDLING AND PERFORMANCE PROPERTIES David Dubowik

Air Products & Chemicals Incorporated 7201 Hamilton Boulevard

Allentown, Pa. 18195 Abstract Garage floor coatings designed for the Do-It-Yourself market must be safe, easy to use, and high performance despite poor surface preparation, application in bad weather, and application by unskilled labor. To identify the best garage floor coatings a variety of polymers were evaluated for critical properties such as adhesion to oil contaminated concrete, abrasion resistance, hot tire pick-up resistance, low temperature cure, pot life, dry time, and VOC content. Several waterborne epoxies were identified which offer high performance along with ease of handling and low or zero VOC. The test methods, results, and other important coating design considerations will be presented along with product recommendations and starting point formulations. Introduction Garage floor and basement floor coatings have become very popular in the do-it-yourself home maintenance market. These coatings must deliver high performance even when applied by unskilled labor to poorly prepared substrates under adverse weather conditions. Our objective was to identify the most effective polymers for garage and concrete floor coatings and to identify any polymers with serious flaws or performance weaknesses. To evaluate the candidates we focused on the following handling & performance characteristics:

1) 1 part or 2 part paints acceptable but not 3 part or water reducible 2) Hand mixing or electric drill mixing 3) Low odor, non-flammable 4) Components and mixed paint must be low irritation and low toxicity 5) Easy clean up preferably with soap & water 6) Paint waste disposable through normal channels 7) Application & Cure at 40°F - 90°F 8) Concrete contaminated with motor oil 9) Cured coating must be durable and abrasion resistant 10) Cured coating must have uniform appearance and performance

For the do-it-yourself market mixing and application must be simple. While one part systems are preferred, two part reactive systems can be used if they require only moderate mixing. Complications such as incremental addition, water thinning, mechanical mixing, or induction time will limit the usefulness of any polymer system.

Appearance & performance must be consistent over a wide temperature & humidity range. Gloss, hardness, adhesion, & abrasion resistance should not change noticeably if one area is coated on a cool damp morning and another area is coated on a hot dry afternoon. Once the paint is applied, return to service must be fast. Performance Targets Pot Life Zero Induction Time, 3 hrs minimum working time Dry Time Tack Free 2 hrs minimum, Hard Dry 24 hrs maximum Adhesion 250 psi minimum Abrasion < 100 mg weight loss (Taber CS 17, 1 Kg, 1,000 cycles) VOC 50 gm/liter, Low Odor Gloss Uniform throughout pot life, Uniform from 50°F to 90°F 50°F Cure No change in gloss, adhesion, hardness, abrasion resistance Pencil Hardness HB - 3H Hot Tire Pick Up No loss of adhesion, Minimal staining Polymer Candidates Further Evaluation ?

Polymer Type Benefits Drawbacks

Yes WB Epoxy Adhesion, Crosslinking 2 Part Limited Working Life

Yes WB Acrylic-Epoxy Ease of Use Thermoplastic Low X-Link Density

Yes WB Polyurethane-Acrylic Ease of Use, Toughness

Thermoplastic Low X-Link Density

No Polyurethane Dispersion Ease of Use, Toughness

High Cost

No 2K Polyurethane Toughness, Crosslinking

Health Issues

No Alkyd Ease of Use Saponification by Alkaline Concrete

Low Odor Low Irritation Water Clean-Up

Polyurethane dispersions, 2K Polyurethanes, and Alkyds were eliminated from further consideration due to fundamental weaknesses including high cost, toxicity concerns, and sensitivity to alkaline environments. Polymer candidates were formulated to 10-20% PVC using TiO2, additives, & co-solvents as needed. See the appendix for representative formulations. Commercial benchmark systems were used as supplied. Waterborne Epoxy Waterborne epoxies form strong thermosetting coatings with good adhesion. Three different waterborne epoxy technologies were evaluated.

• Type I - Water Soluble Amine + Liquid Epoxy • Type II - Water Soluble Amine + Solid Epoxy Dispersion • Type III - Amine Dispersion + Epoxy

Type I WB Epoxy Type I curing agents emulsify liquid epoxy in water. The emulsion forms when the A & B components of the paint are mixed together. These systems require good shear to ensure uniform mixing. Liquid epoxy systems coalesce easily but do not lacquer dry. Drying is slow, depending more on chemical reaction than physical drying. Pot life is short due to the high reactivity of liquid epoxy and the end of pot life is signalled by rapid viscosity increase or destabilization of the emulsion. Type I coatings develop high hardness, low flexibility, and good chemical resistance. Type II Waterborne Epoxy Type II WB epoxies utilize solid epoxy pre-dispersed in water.

Water Soluble Amine+

Epoxy Dispersion

Surfactant

Liquid Epoxy

Water Soluble Amine

Water-Amine-EpoxyEmulsion-Solution+

High Shear Amine-Epoxy

Emulsion in Water

The epoxy and amine are easily mixed with low shear. The amine migrates from the water into the dispersed particle where it reacts with epoxy. An induction time is used to allow for amine movement from the water phase into the epoxy phase. Pot life is typically 3-8 hrs. The solid epoxy resins used in Type II systems provide fast lacquer dry but also typically require co-solvents for good coalescence. As pot life progresses, the dispersed particles harden and can no longer coalesce. End of pot life is determined by loss of coalescence, easily observed as loss of gloss in the dry film, but not visible as an increase in viscosity. Type II systems therefore have a blind pot life. Type III Waterborne Epoxy Type III systems use an amine dispersion combined with a solid epoxy dispersion or with liquid epoxy. Type III Amine Dispersion + Solid Epoxy Dispersion

Type III Amine Dispersion + Liquid Epoxy

When using solid epoxy dispersions it is very important that the particles coalesce and fuse together into a homogeneous film. When using liquid epoxy it is very important to get the epoxy completely emulsified during the mixing process. Amine dispersions are hydrophobic. When combined with hydrophobic epoxies, they can cross-link into polymers with very high water resistance.

Amine

Dispersion + Liquid

Epoxy

Epoxy

Dispersion Amine

Dispersion +

Acrylic-Epoxy Acrylic-epoxy is a waterborne latex emulsion containing both thermoplastic acrylic and epoxy resin. The epoxy may crosslink with carboxylic acid groups on the acrylic or it may act as a hydrophobic plasticizer which improves water resistance. Urethane-Acrylic Urethane-Acrylic hybrids combine the performance of a PUD with the lower cost of an acrylic. We evaluated a unique Urethane-Acrylic hybrid in which the polyurethane and acrylic form an interpenetrating network in the same dispersed particle. This approach yields PUD performance but at significantly lower cost. Experimental Systems Label Curing Agent Epoxy Polymer Features A Anquamine™ 401 DLE1 Type I WB Epoxy Fast Cure B Anquamine 701 DLE1 Type I WB Epoxy Fast Dry C Epilink™ 360 DLE1 Type I WB Epoxy Cost Effective D Anquamine 701 (50%)

Epilink 360 (50%) DLE1 Type I WB Epoxy Balanced Properties

E Anquawhite™ 100 DLE1 Type III WB Epoxy Low Color WB WB Epoxy Control DLE1 Type I WB Epoxy Commercial Benchmark G Anquamine 401 SED2 Type II WB Epoxy Fast Dry H Anquawhite 100 SED2 Type III WB Epoxy Fast Dry, Low Color SB Ancamine™ 2143 SSES3 Solvent Borne Epoxy Concrete Penetration TP1 Hybridur™ 870-878 --- Polyurethane-Acrylic Tough, Durable TP2 Hybridur 570-580 --- Polyurethane-Acrylic Tough, Durable AE Acrylic-Epoxy --- Acrylic-Epoxy Commercial Benchmark 1 DLE - Liquid Epoxy diluted with C12-14 epoxy diluent (Epodil 748) 2 SED - Solid Epoxy Dispersion (Ancarez™ AR 550) 3 SSES - Semi-solid Epoxy Solution in PM solvent Test Methods Concrete Test Panels Test panels (3” x 6”) were prepared using portland cement mortar (ASTM C 109 type) cured at least 28 days. Prior to use, each concrete panel was coated with 10 mils of 10-W-30 motor oil then heated 16 hrs @ 35°C to allow the motor oil to penetrate the concrete.

Hot Tire Pick-Up Resistance Driving an automobile into a garage can be a major challenge for a newly applied floor coating. In addition to applying heat and pressure, automobile tires, especially new tires, contain petroleum oils and tars that can stain and soften the coating. Staining & delamination are common problems for freshly applied garage floor coatings. Hot Tire Pick Resistance Testing Tread from a new general purpose tire was used to ensure high levels of petroleum oils & tars. The coated concrete panel & tire tread were heated and pressure was applied to simulate an automobile being driven into a freshly painted garage. Test Procedure:

• New automobile tire tread. • 40-45 psi pressure applied using 5 pound lead ingots • Heat to 50°C for 2 hrs. • Wipe tire stains with soft cloth & Formula 409 cleaner prior to evaluation

Evaluate Delamination Staining Blistering Softening

Pot Life / Working Life - Two part reactive systems have a limited working life. Once the reactants are mixed the molecular weight increases until high viscosity or loss of coalescence renders the material unusable. End of pot life may be visible or blind. Visible end of pot life is signalled by a rapid increase in viscosity or destabilization of the emulsion and is easily observed by the applicator. Blind pot life provides no indications to the applicator. Polymer viscosity and minimum film forming temperature increase but the polymer in the dispersed phase has minimal effect on formulation viscosity. Loss of coalescence signals the end of pot life and is only visible when the paint dries to a weak low gloss or flaky film.

In general Type I waterborne epoxies have visible end of pot life while Type II systems have blind pot lives. Thermoplastic systems are non-reactive and therefore have no limits on working life. Dry Time / Open Time - Freshly applied paint should remain tacky for at least 1-2 hours. During this tacky period decorative accents can be broadcast onto the coating and a wet edge can be maintained. Systems with fast dry times may be easy of use but they are not amenable to broadcasting paint chips or anti-skid additives.

0

1

2

3

4

5

6

A B C D E WB G H SB

Visible End of Pot Life

Pot Life (hr)

Set to Touch Times

Type I waterborne epoxies exhibit slower dry times whereas Type II waterborne epoxies and thermoplastics exhibit much faster dry times. Hardness For concrete substrates subjected to heavy traffic, hard coatings are more suitable than soft coatings. Waterborne epoxies, due to their crosslinking and rigid polymer segments, deliver much harder coatings than the thermoplastic polymers. All of the epoxy systems developed adequate hardness whereas the thermoplastic systems were softer and more likely to be damaged.

0

1

2

3

4

5

6

A B C D E WB G H SB TP1 TP2 AE

Set to Touch (hrs)

0

1

2

3

4

5

6

7

8

9

10

Penc

il H

ardn

ess

A B C D E WB G H SB TP1 TP2 AE

2H

H

F

HB

B

2B

3B

4B

5B

6B

Adhesion to Oil Contaminated Concrete Coated panels were tested that were both detergent cleaned and non-cleaned. For non-cleaned panels, paint was applied directly to the oily concrete with no surface preparation. For detergent cleaned panels, the oily panels were scrubbed with commercial garage floor degreaser and rinsed with water prior to application of the wet paint. Adhesion was measured by dolly pull-off using a minimum of three test sites per panel.

Detergent cleaned panels showed only slight improvements in adhesion versus non-cleaned panels. Not surprisingly solvent borne epoxy with its low viscosity and good wetting characteristics offered the highest adhesion at 375-400 psi. Type I epoxies in general developed better adhesion than the Type II or Type III epoxies. The acrylic-urethane hybrids and the acrylic-epoxy developed significantly lower adhesion than the waterborne epoxies. The superior adhesion of Type I waterborne epoxies is likely due to the smaller lower viscosity molecules penetrating into smaller pores and penetrating more deeply into the concrete. The larger size and higher viscosity of the other polymers hinders penetration and reduces the number of anchor sites in the concrete.

0

100

200

300

400

A B C D E WB G H SB TP1 TP2 AE

Bon

d S

treng

th (p

si)

Detergent Cleaned

Non-Cleaned

Hot Tire Pick Up Resistance Ratings 1 - heavy stain, delamination 3 - heavy stain, slight delamination 5 - medium stain, no delamination 7 - light stain 9 - very light stain 10 - no effect All of the epoxy systems eventually developed complete resistance to hot tire pick-up while the thermoplastics remained susceptible to heavy staining 10 days after application. Systems B, C, & D (based on Anquamine 701 & Epilink 360) were particularly effective with only moderate staining after 4 days cure. Appearance & Durability System VOC (g/L) RT Gloss 40°F Gloss 40°F Adhesion

(non-cleaned) Abrasion Resistance

A 0 50 50 170 psi --- B 0 20 20 300 psi 85 C 0 55 50 280 psi 95 D 0 50 50 290 psi 95 E 50 15 15 160 psi --- WB ND 55 50 230 psi 85 G 0 25 20 200 psi 85 H 50 15 15 170 psi --- SB 330 70 50 350 psi --- TP1 155 40 --- --- --- TP2 140 40 --- --- --- AE --- 10 --- --- ---

0

1

2

3

4

5

6

7

8

9

10

B C D WB G SB TP1 TP2 AE

Hot

Tire

Res

ista

nce

10 day cure

4 Day Cure

2 Day Cure

1 Day Cure

In general the waterborne epoxies showed little difference in appearance or performance when cured at low temperature. Systems A, E, H, TP1, TP2, and AE were eliminated from further consideration due to poor adhesion General Trends System Adhesion Hot Tire Pot Life Open Time Low VOC

Type I WB Epoxy Type II WB Epoxy Type III DLE* Type III SED** SB Epoxy x Acrylic-PUD Acrylic Epoxy DLE* Diluted Liquid Epoxy SED** Solid Epoxy Dispersion in Water Type I waterborne epoxies have a short working life but otherwise offer a good balance of handling & performance. Type II waterborne epoxies offer longer working life & faster dry but with reduced adhesion. Type III epoxy, acrylic-polyurethane, and acrylic-epoxy all produced lower adhesion and were judged less desirable for this application. Solvent borne epoxy while offering good overall performance is impractical for consumer use due to strong odor and flammability. Summary & Recommendations This graph plots each critical property on a 1-10 scale using 10 as an optimum score (for example: very low cost = 10 very high cost = 1). The best candidates have the largest area inside the pentagon.

Adhesion

Cost

Hot TireVOC

HandlingEpilink 360

Anquamine 701

701-360 Blend

Anq 401 - Ancarez™ AR 550

WB Control

The Type I waterborne epoxy based on Epilink 360 offers the best balance of handling, performance, & cost. Adhesion & cure speed can enhanced by blending Anquamine 701 with Epilink 360. The Type II system based on Anquamine 401 + Ancarez™ AR 550 is a viable option where fast dry & long working life are desirable properties. Acknowledgements Many thanks to my colleagues including Jill Dorneman, Tracy Wickman, and Ellen O’Connell whose contributions made these technologies and test results possible. For further information, please contact us at http://www.airproducts.com/EpoxyAdditives Attachments Epilink 360 Type I Waterbased Epoxy

Raw Material Pounds GallonsA Side

Epon™ 828 188.11 19.43 Epodil™ 748 41.29 5.56 229.41 24.99

B Side Epilink 360 320.74 36.60 DI H2O 263.45 31.56 Igepal™ CO 897 7.68 0.84 Byk™ 034 4.80 0.65 TiPure™ R 960 174.68 5.37 771.34 75.01

Totals 1000.75 100.00 PVC 11% VOC (lb/gal) 0% Wt Solids 74% Vol Solids 50%

Anquamine 701 Type I Water Based Epoxy

Raw Material Pounds GallonsA Side

Epon 828 188.20 19.44 Epodil 748 41.31 5.56 229.51 25.00

B Side Anquamine 701 343.81 37.45 DI H2O 229.69 27.52 Surfynol™ 420 0.30 0.04 Surfynol CT 111 6.51 0.78 Surfynol DF 110D 6.21 0.74 TiPure R 960 276.03 8.48 862.55 75.00

Totals 1092.06 100.00 PVC 15.77% VOC (lb/gal) 0.000 Wt Solids 78.97% Vol Solids 53.76%

Anquamine 401 Type II Waterborne Epoxy

Raw Material Pounds Gallons A Side

Ancarez AR 550 606.50 66.66

B Side Anquamine 401 97.04 10.67 Defoamer 4.62 0.55 DI Water 96.46 11.56 Surfynol 420 2.31 0.26 TiPure R 706 254.15 7.81 Total 475.38 33.34

Total 1081.87 100.00

PVC 15% VOC (lb/gal) 0% Wt Solids 62% Vol Solids 53%